A razor blade is typically formed of a suitable substrate material such as stainless steel, and a cutting edge is formed with a wedge-shaped configuration with an ultimate tip having a radius. Hard coatings such as diamond, amorphous diamond, diamond-like carbon-(DLC) material, nitrides, carbides, oxides, or ceramics are often used to improve strength, corrosion resistance, and shaving ability, maintaining needed strength while permitting thinner edges with lower cutting forces to be used. Polytetrafluoroethylene (PTFE) can be used to provide friction reduction. Layers of niobium or chromium containing materials can aid in improving the binding between the substrate, typically stainless steel, and hard carbon coatings, such as DLC.
It is desirable to alter the shape of the razor blade to achieve a razor blade with a low cutting force, while at the same time improving safety and comfort. By finding the ideal edge design it is possible to provide a low cutting force blade that is safer on the skin leading to a more comfortable shave.
Prior blades improved shaving comfort by reductions in tip radii and overall profile cross-section, reducing the tug-and-pull associated with cutting through hair. These sharper edges however required special implementation to avoid discomfort associated with the blade-skin interactions. Also, as a consequence of thinning the blade bevel profile, strength and durability can be compromised.
The present invention addresses the problems of balancing the desire for low cutting force, increased safety, and increased comfort. The present invention provides a blade tip having a wider forward profile near the blade tip with a small tip radius while maintaining a narrow profile away from the blade tip.
The large forward profile near the tip in conjunction with a narrow blade profile further away from the tip provides a low cutting force blade edge that has less propensity to engage the skin allowing the skin to glide over the edge without nicking, cutting or scraping. Such a blade reduces irritation and increases comfort.